scholarly journals GLUCOSE-6-PHOSPHATASE IN THE SALIVARY GLANDS OF SCIARA COPROPHILA: A HISTOCHEMICAL AND BIOCHEMICAL STUDY

1965 ◽  
Vol 13 (3) ◽  
pp. 168-181 ◽  
Author(s):  
JACOB Y. TERNER ◽  
REBA M. GOODMAN ◽  
DAVID SPIRO
Keyword(s):  
Endoplasmic Reticulum ◽  
Phosphatase Activity ◽  
Biochemical Study ◽  
Minimal Amount ◽  
Prolonged Incubation ◽  
Larval Stages ◽  
Larval Salivary Gland ◽  
Mammalian Liver ◽  
Specific Proteins ◽  
Relationship Of

Biochemical characteristics of an enzyme in larval stages of Sciara coprophila specifically hydrolyzing glucose-6-phosphate are shown to parallel those of a similar enzyme in mammalian liver with respect to substrate specificity and reactivity in the presence of various inhibitors. Even with prolonged incubation this enzyme can be demonstrated histochemically in unfixed larval salivary gland of Sciara coprophila only in focal dilated cisternae of the rough surfaced endoplasmic reticulum. It was concluded that the morphologically homogeneous microsomal system may have areas of biochemical specialization which allow the production of specific proteins (in this case a glucose-6-phosphatase) made in no other portion of the rough surfaced endoplasmic reticulum. Glucose-6-phosphatase activity is absent biochemically during the 2nd and 3rd instars. A minimal amount is present in the 4th instar and a marked elevation occurs prior to pupation; this level is maintained during pupation. Histochemically, glucose-6-phosphatase activity can be demonstrated throughout the larval stage. The relationship of the characteristic 4th instar puffs of dipteran larval chromosomes to the onset of high levels of glucose-6-phosphatase activity is discussed.

scholarly journals ON THE RELATIONSHIP OF LIVER GLUCOSE-6-PHOSPHATASE TO THE PROLIFERATION OF ENDOPLASMIC RETICULUM IN PHENOBARBITAL INDUCTION

1966 ◽  
Vol 31 (2) ◽  
pp. 243-256 ◽  
Author(s):  
Sten Orrenius ◽  
Jan L. E. Ericsson
Keyword(s):  
Endoplasmic Reticulum ◽  
Phosphatase Activity ◽  
Actinomycin D ◽  
Microsomal Enzymes ◽  
High Drug ◽  
Histochemical Methods ◽  
Relationship Of ◽  
The Relationship ◽  
Phenobarbital Induction ◽  
Liver Microsomal Enzymes

The differentiated effects of phenobarbital treatment on liver microsomal enzymes have been further studied. The relationship between the resulting decrease in the specific glucose-6-phosphatase activity and the enhancement of formation of endoplasmic reticulum membranes with high drug-hydroxylating activity has been investigated with biochemical and histochemical methods. Biochemically and histochemically demonstrable glucose-6-phosphatase activity was found to be present in all endoplasmic reticulum membranes, including the phenobarbital-induced smooth-surfaced proliferates, even though there was an over-all decrease in activity. Actinomycin D did not inhibit the decrease in glucose-6-phosphatase activity. The findings are discussed with reference to the enzyme-membrane relationship in phenobarbital induction.

Virtual Screening, Molecular Modelling and Biochemical Studies to Exploit PF14_0660 as a Target to Identify Novel Anti-malarials

2019 ◽  
Vol 16 (4) ◽  
pp. 417-426
Author(s):  
Vimee Raturi ◽  
Kumar Abhishek ◽  
Subhashis Jana ◽  
Subhendu Sekhar Bag ◽  
Vishal Trivedi
Keyword(s):  
Virtual Screening ◽  
Phosphatase Activity ◽  
Molecular Modelling ◽  
Drug Target ◽  
Antimalarial Activity ◽  
Biochemical Study ◽  
Tyrosine Phosphatase ◽  
Host Protein ◽  
Dependent Manner ◽  
Multiple Sequence

Background: Malaria Parasite relies heavily on signal transduction pathways to control growth, the progression of the life cycle and sustaining stress for its survival. Unlike kinases, Plasmodium's phosphatome is one of the smallest and least explored for identifying drug target for clinical intervention. PF14_0660 is a putative protein present on the chromosome 14 of Plasmodium falciparum genome. Methods: Multiple sequence alignment of PF14_0660 with other known protein phosphatase indicate the presence of phosphatase motif with specific residues essential for metal binding, catalysis and providing structural stability. PF14_0660 is a mixed α/β type of protein with several β -sheet and α-helix arranged to form βαβαβα sub-structure. The surface properties of PF14_0660 is conserved with another phosphate of this family, but it profoundly diverges from the host protein tyrosine phosphatase. PF14_0660 was cloned, over-expressed and protein is exhibiting phosphatase activity in a dose-dependent manner. Docking of Heterocyclic compounds from chemical libraries into the PF14_0660 active site found nice fitting of several candidate molecules. Results: Compound PPinh6, PPinh 7 and PPinh 5 are exhibiting antimalarial activity with an IC50 of 1.4 ± 0.2µM, 3.8 ± 0.3 µM and 9.4 ± 0.6&#181M respectively. Compound PPinh 6 and PPinh 7 are inhibiting intracellular PF14_0660 phosphatase activity and killing parasite through the generation of reactive oxygen species. Conclusion: Hence, a combination of molecular modelling, virtual screening and biochemical study allowed us to explore the potentials of PF14_0660 as a drug target to design anti-malarials.

scholarly journals High-yield monolayer graphene grids for near-atomic resolution cryoelectron microscopy

2019 ◽  
Vol 117 (2) ◽  
pp. 1009-1014 ◽  
Author(s):  
Yimo Han ◽  
Xiao Fan ◽  
Haozhe Wang ◽  
Fang Zhao ◽  
Christopher G. Tully ◽  
...  
Keyword(s):  
Structural Biology ◽  
Structural Investigation ◽  
High Yield ◽  
Monolayer Graphene ◽  
Minimal Amount ◽  
Biological Macromolecules ◽  
Atomic Structures ◽  
Specific Proteins ◽  
Protein Density ◽  
Working Mechanisms

Cryogenic electron microscopy (cryo-EM) has become one of the most powerful techniques to reveal the atomic structures and working mechanisms of biological macromolecules. New designs of the cryo-EM grids—aimed at preserving thin, uniform vitrified ice and improving protein adsorption—have been considered a promising approach to achieving higher resolution with the minimal amount of materials and data. Here, we describe a method for preparing graphene cryo-EM grids with up to 99% monolayer graphene coverage that allows for more than 70% grid squares for effective data acquisition with improved image quality and protein density. Using our graphene grids, we have achieved 2.6-Å resolution for streptavidin, with a molecular weight of 52 kDa, from 11,000 particles. Our graphene grids increase the density of examined soluble, membrane, and lipoproteins by at least 5-fold, affording the opportunity for structural investigation of challenging proteins which cannot be produced in large quantity. In addition, our method employs only simple tools that most structural biology laboratories can access. Moreover, this approach supports customized grid designs targeting specific proteins, owing to its broad compatibility with a variety of nanomaterials.

scholarly journals CYTOLOGICAL STUDIES ON TWO FUNCTIONAL HEPATOMAS

1962 ◽  
Vol 15 (2) ◽  
pp. 289-312 ◽  
Author(s):  
Edward Essner ◽  
Alex B. Novikoff
Keyword(s):  
Endoplasmic Reticulum ◽  
Acid Phosphatase ◽  
Golgi Apparatus ◽  
Phosphatase Activity ◽  
Acid Phosphatase Activity ◽  
Secretory Granules ◽  
Dynamic State ◽  
Secretory Product ◽  
Electron Microscopic ◽  
Golgi Membranes

The Reuber hepatoma H-35 and Morris hepatoma 5123 have been studied by electron microscopy and by cytochemical staining methods for a number of phosphatases. These studies emphasize the resemblances of the two tumors to rat liver, but they also indicate distinctive features in each of the three tissues. Secretory product accumulates within the cisternae of the Golgi apparatus that dilate to form the Golgi vacuoles. The vacuoles apparently separate, and secretory material undergoes further condensation within them. These "secretory vacuoles" possess acid phosphatase activity and may thus be considered lysosomes. The membranes of the Golgi apparatus are without acid phosphatase activity but show high levels of thiaminepyrophosphatase activity. The endoplasmic reticulum also hydrolyzes thiaminepyrophosphate but at a lower rate; it hydrolyzes the diphosphates of uridine, guanosine, and inosine rapidly. These observations and the electron microscopic images are consistent with the view that the cytomembranes are in a dynamic state of flux, movement, and transformation in the living cell, and that smooth surfaced derivatives of the endoplasmic reticulum become refashioned into the Golgi membranes as the Golgi membranes are being refashioned into those that delimit secretory vacuoles. The variations encountered in the two hepatomas are described. The electron microscope literature dealing with the relations of the Golgi apparatus to secretory granules, on the one hand, and the endoplasmic reticulum, on the other, is reviewed briefly.

Cellular mechanisms of periostracum formation in Physa spp. (Mollusca: Pulmonata)

1978 ◽  
Vol 56 (11) ◽  
pp. 2299-2311 ◽  
Author(s):  
G. M. Jones ◽  
A. S. M. Saleuddin
Keyword(s):  
Endoplasmic Reticulum ◽  
Acid Phosphatase ◽  
Phosphatase Activity ◽  
Rough Endoplasmic Reticulum ◽  
Acid Phosphatase Activity ◽  
Homogeneous Material ◽  
Cellular Mechanisms ◽  
Phenoloxidase Activity ◽  
Enzyme Substrate ◽  
Mantle Edge

The periostracum comprises an external lamella, 13 nm thick, and one sublamellar layer. Periostracal cells secrete the lamella as preformed periostracal units. The mantle edge gland (meg) produces most of the sublamellar layer. A sequence of formation of periostracal units within the periostracal cells is suggested. Homogeneous inclusions, possibly Golgi derived, fuse into larger, irregular inclusions. Within these inclusions, three-layered membranes, 7 nm thick, arise from the homogeneous material. The membranes fuse in pairs to form the five-layered, 13-nm periostracal units. Acid phosphatase activity has been localised al the surfaces of the periostracal units and might be involved in modifying the units prior to their discharge. Phenoloxidase and polyphenols have been localised in the meg, suggesting that this region is responsible for periostracal sclerotisation. Phenoloxidase activity is present in Golgi, rough endoplasmic reticulum, and apical secretory inclusions in cells in the anterior two-thirds of the meg. Polyphenols are present in apical secretory inclusions, particulary in three or four cells in the posterior meg. This distribution may suggest that phenoloxidase is incorporated into all levels of the sublamellar layer and that sclerotisation occurs subsequently when the enzyme substrate is presented.

Serum Cytokine Receptors in Ankylosing Spondylitis: Relationship to Inflammatory Markers and Endoplasmic Reticulum Aminopeptidase Polymorphisms

2010 ◽  
Vol 37 (9) ◽  
pp. 1907-1910 ◽  
Author(s):  
NIGIL HAROON ◽  
FLORENCE W.L. TSUI ◽  
BASIL CHIU ◽  
HING WO TSUI ◽  
ROBERT D. INMAN
Keyword(s):  
Endoplasmic Reticulum ◽  
Ankylosing Spondylitis ◽  
Disease Activity ◽  
Cytokine Receptor ◽  
Cytokine Receptors ◽  
Serum Cytokine ◽  
Markers Of Inflammation ◽  
Significant Difference ◽  
Cytokine Levels ◽  
Relationship Of

Objective.Endoplasmic reticulum aminopeptidase (ERAP)1 is associated with ankylosing spondylitis (AS) and is known to be involved in the clipping of the cytokine receptors interleukin 1 receptor II (IL-1RII), IL-6Rα, and tumor necrosis factor receptor I (TNFRI). We studied the relationship of these serum cytokine receptors and their corresponding cytokines to markers of inflammation and polymorphisms in ERAP1 and ERAP2 in patients with AS.Methods.Sera from patients with AS were assayed for TNF-α, IL-1, IL-6, sTNFRI, sIL-1RII, and sIL-6Rα by ELISA. Genotyping was performed for 3 AS-associated nonsynonymous single-nucleotide polymorphisms in the ERAP1 gene [rs27044(C/G), rs10050860(C/T), and rs30187(C/T)] and 1 in the ERAP2 gene [rs2549782(T/G)]. The serum cytokine and receptor levels were compared between the different genotype groups and correlated to markers of inflammation and disease activity.Results.Eighty patients with AS (21 women) with a mean Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) of 5.3 ± 2.4 were enrolled. There was a significant correlation of sTNFRI with C-reactive protein (CRP; R = 0.43, p < 0.001) and erythrocyte sedimentation rate (ESR; R = 0.30, p = 0.01) but not with BASDAI. Serum cytokine levels were undetectable in the majority of patients. There was no significant difference in serum cytokines or the soluble receptors between patients with the different ERAP1/ERAP2 polymorphisms and their haplotypes. Similarly, there was no relationship of the polymorphisms with the serum cytokine levels nor the cytokine-receptor ratio.Conclusion.Soluble TNFRI levels correlate with ESR and CRP in AS. The ERAP1 and ERAP2 polymorphisms associated with AS do not influence the serum cytokine receptor levels in patients with AS.

Relationship of acid phosphatase activity and Brix/acid ratio in apples

LWT ◽  
2005 ◽  
Vol 38 (2) ◽  
pp. 181-183 ◽  
Author(s):  
Kyung Young Yoon ◽  
Edward E. Woodams ◽  
Yong D. Hang
Keyword(s):  
Acid Phosphatase ◽  
Phosphatase Activity ◽  
Acid Phosphatase Activity ◽  
Acid Ratio ◽  
Relationship Of
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